80-4280-10, Rev. 4
27
Note that changing direction of travel using any
of the previous three methods alone will result in a
properly functioning CCW actuator; however, the
2-wire Position feedback signal from the actuator’s
CPS-4 will be reverse-acting or opposite the Demand
signal (i.e., a 4–20 mA Demand signal to the actuator
will have a corresponding feedback signal of 20–4
mA). If a direct-acting feedback is desired (4–20 in
equals 4–20 out) then use Procedure 2 below.
Procedure 2
This procedure changes the direction of actuator
travel and also reverses the 2-wire Position feedback
signal so it remains direct-acting and directly
proportional to the Demand input signal (i.e., applying
a 4–20 mA Demand input to the actuator results in a
4–20 mA Position feedback signal response). This
procedure requires more steps than the previous
procedure outlined above.
1. Position the actuator to its 0% position and
place the Handswitch in “STOP”. Make sure
the 2-wire Position feedback signal reads 4 mA.
2. Change the CPS Rotation setting to match the
desired actuator travel. For example, when
changing the actuator’s direction of travel from
CW to CCW you will also need to change the
CPS rotation setting in the DCM configuration
from CW to CCW. This change can only be
made using a serial command via the DCM
serial port. Use serial command “cpsrotation
n
”,
where
n
= 0 to set CW rotation and
n
= 1 to set
CCW rotation.
3. Set the CPS Rotation switch on the CPS-4
(see image below) to match the CPS rotation
setting established in step 2 above. To change
from CW to CCW, rotate the switch fully CCW
(approx. 27
0º) to the switch’s hard stop. Do
the opposite to change from CCW to CW. Note
that the CPS rotation normally must match the
actuator direction of travel in order for the 2-wire
Position feedback signal to be direct-acting with
respect to the Demand input signal.
4. At this point, the 2-wire Position feedback
from the CPS should have shifted from 4 mA
to a value closer to the 100% value of 20 mA.
Make a note of the offset between the feedback
reading and the desired 20 mA value and adjust
the Zero pot. on the
CPS-4 (see image below)
as required to bring the feedback signal back
to 20 mA (the new desired value).
5. Change the actuator direction of travel using
one of the three methods outlined in Procedure
1, above (i.e., HART, Pushbuttons or Serial).
6. Place the Handswitch in “AUTO” and verify
proper operation of the actuator.
CPS-4 ROTATION SWITCH & ZERO POT. (BOTH VERSIONS SHOWN)
ROTATION
SWITCH (S1)
ZERO POT.
